An electronic
cigarette (e-cig or e-cigarette), personal vaporizer (PV)
or electronic nicotine delivery system (ENDS) is a battery-powered vaporizer that feels
similar to tobacco smoking. The user
inhales an aerosol, commonly called vapor,
rather than cigarette smoke.
E-cigarettes typically have a heating element that atomizes a liquid solution known as e-liquid. E-cigarettes are generally
cylindrical, with many variations. There are disposable or reusable versions.
E-liquids usually contain propylene glycol, glycerin, nicotine, and flavorings. E-liquids are also sold
without propylene glycol, without nicotine, or without flavors.
The
benefits and health risks of electronic
cigarettes are uncertain. One review found limited evidence of a
benefit as a smoking cessation aid, but
there is no evidence they are
better than regulated medication for quitting smoking. Their usefulness in tobacco harm reduction is unclear. One review found their safety risk is similar to that of smokeless tobacco. Another found United States Food and Drug Administration (FDA)-approved products, such as nicotine inhalers, are probably safer than e-cigarettes.
better than regulated medication for quitting smoking. Their usefulness in tobacco harm reduction is unclear. One review found their safety risk is similar to that of smokeless tobacco. Another found United States Food and Drug Administration (FDA)-approved products, such as nicotine inhalers, are probably safer than e-cigarettes.
Limited evidence suggests e-cigarettes are
safer than traditional cigarettes. People who do not already
smoke can become addicted to them. There is no evidence e-cigarettes are
regularly used by those who have never smoked. E-cigarette use may delay or
deter quitting smoking. E-cigarettes create vapor that consists of ultrafine particles. The
vapor contains similar chemicals to the e-liquid, together with tiny amounts of
toxicants and heavy metals. E-cigarette vapor contains fewer toxic
substances than cigarette smoke, and is likely to be less harmful than
traditional cigarettes to users and bystanders. No serious adverse effects from e-cigarettes have been reported in
trials. Less serious adverse effects include throat and mouth inflammation,
vomiting, nausea, and cough. The long-term effects of e-cigarette use are
unknown.
Construction
An electronic cigarette is a battery-powered vaporizer which
provides a flavor and feel similar to tobacco
smoking, but there are differences. A noticeable difference between
the traditional cigarette and the e-cigarette is sense
of touch. The user inhales an aerosol,
commonly called vapor,
rather than cigarette smoke. Once the
user inhales, the airflow activates the sensor, and then the heating
element atomizes the liquid
solution inside the cartridge into vapor. Other e-cigarettes have a
manual push-button switch to turn on the device. E-cigarettes are generally
cylindrical, with many variations. Some e-cigarettes look like traditional
cigarettes, but others do not. There are three main categories of e-cigarettes:
cigalikes, looking like cigarettes; eGos, bigger than cigalikes with refillable
liquid tanks; and mods, assembled from basic parts or by altering existing
products. There are disposable or reusable versions. E-cigarettes that resemble
pens or USB memory sticks are also sold for those who may want to use the
device unobtrusively.
First
generation e-cigarettes tend to look like tobacco cigarettes and so are called
"cigalikes". Second generation devices tend to be used by more
experienced users. Third generation devices include mechanical mods and
variable voltage devices. A fourth generation digital e-cigarette became
available in the U.S. in 2014. As the e-cigarette industry is growing, new
products are quickly developed and brought to market. The devices contain a rechargeable battery,
which tends to be the largest component of an e-cigarette.
Health effects
As
of 2014 electronic cigarettes had not been approved as a smoking cessation
device by any government. In July 2014, a report produced by the World Health Organization
(WHO) for the WHO Framework Convention on
Tobacco Control, found there was not enough evidence to determine if
electronic cigarettes can help people quit smoking. It suggested that smokers
should be encouraged to use approved methods for help with quitting. But the
same report also mentioned expert opinions in scientific papers that suggested
e-cigarettes may have a role helping people quit who have failed using other
methods. A previous WHO statement from July 2013 said that e-cigarettes have
not been shown to help people quit smoking. It also recommended that
"consumers should be strongly advised not to use" e-cigarettes unless
a reputable national regulatory body has found them safe and effective. The World Lung Foundation
applauded the WHO report's recommendation for tighter regulation of
e-cigarettes due to concerns about the safety of e-cigarettes and the risk of
increased nicotine or tobacco addiction among youth.
The
UK National Health Service
concluded that "While e-cigarettes may be safer than conventional
cigarettes, we don't yet know the long-term effects of vaping on the body.
There are clinical trials in progress to test the quality, safety and
effectiveness of e-cigarettes, but until these are complete and the government
can't give any advice on them or recommend their use."
In
2014, the US Food and Drug Administration
(FDA) said "E-cigarettes have not been fully studied, so consumers
currently don't know: the potential risks of e-cigarettes when used as
intended, how much nicotine or other potentially harmful chemicals are being
inhaled during use, or whether there are any benefits associated with using
these products. Additionally, it is not known whether e-cigarettes may lead
young people to try other tobacco products, including conventional cigarettes,
which are known to cause disease and lead to premature death.
Harm reduction
Tobacco harm reduction has
been a controversial area of tobacco control. The health community has not
endorsed e-cigarettes as a tobacco harm reduction strategy, in part in response
to tobacco industry deception.
A 2014 review concluded promotion of vaping as a harm reduction aid is
premature. Another review found e-cigarettes would likely be less harmful than
traditional cigarettes to users and bystanders. The authors warned against the
potential harm of excessive regulation and advised health professionals to
consider advising smokers who are reluctant to quit by other methods to switch
to e-cigarettes as a safer alternative to smoking. A 2014 review argued that
regulations for e-cigarettes should be similar to those for dietary supplements
or cosmetic products to not limit their potential for harm reduction. Vaping
may have potential in harm reduction compared to smoking. When used to quit
smoking, they could reduce harm even more if the tobacco user quits but
e-cigarettes are not harmless because nicotine has long-term adverse effects,
may contain impurities, and nicotine is addictive, which may have serious side
effects, particularly if users use unconventional ways to increase the doses of
nicotine exposure. A 2012 review found electronic systems appear to generally
deliver less nicotine than smoking, raising the question of whether they can
effectively substitute for tobacco smoking over a long-term period. A 2012
review found e-cigarettes could considerably reduce traditional cigarettes use
and they likely could be used as a lower risk replacement for traditional
cigarettes, but there is not enough data on the safety and efficacy to draw
definite conclusions. E-cigarette use for risk reduction in high-risk groups
such as people with mental disorders is unavailable.
Read
more on: http://en.wikipedia.org/wiki/Electronic_cigarette